Table Alias Vs Column Alias in sql server
Sql Server offers an option to give temporary alias
name for the Table and it’s Column Names in the query. In that way we can give a
meaning full alias to the Tables. And if two tables are joined both have the
same column name, then we have to write two part column names i.e. [Table
Name].[Column Name] otherwise Sql server gives an ambiguous column name error.
If table name is too long it looks to awkward, so better give a alias name to
the table and use this alias name in the Two part column name order to avoid
ambiguity.
Table Alias Name. In
this Query for Emp_Details Table the alias name specified is Emp in the FROM
clause. Because of this we can access the table column names by prefixing Emp.
|
SELECT Emp.Name, Emp.Phone FROM dbo.Emp_Details
Emp
|
Column Name Alias. In
this Query for Emp_Details Table the alias name specified is Emp in the FROM
clause. Because of this we can access the table column names by prefixing Emp.
And for the Name column we are specifying the alias
name as ‘Emp Name’ and for Phone column the alias name is ‘Phone Number
|
SELECT Emp.Name AS 'Emp Name', E.Phone AS [Phone Number]
FROM dbo.Employee AS Emp
|
